1. Field of the Invention
Embodiments of the invention generally relate to apparatus and methods for expanding a tubular in a wellbore. More particularly, embodiments of the invention relate to a compliant cone capable of expanding a tubular while compensating for restrictions where expansion cannot occur.
2. Description of the Related Art
Hydrocarbon wells are typically initially formed by drilling a borehole from the earth's surface through subterranean formations to a selected depth in order to intersect one or more hydrocarbon bearing formations. Steel casing lines the borehole, and an annular area between the casing and the borehole is filled with cement to further support and form the wellbore. Several known procedures during completion of the wellbore utilize some type of tubular that is expanded downhole, in situ. For example, an intermediate string of casing can hang from a string of surface casing by expanding a portion of the intermediate string into frictional contact with a lower portion of the surface casing therearound. Additional applications for the expansion of downhole tubulars include expandable open-hole or cased-hole patches, expandable liners for mono-bore wells, expandable sand screens and expandable seats.
Various expansion devices exist in order to expand these tubulars downhole. Typically, expansion operations include pushing or pulling a solid cone through the tubular in order to expand the tubular to a larger diameter based on a fixed maximum diameter of the cone. However, the solid cone provides no flexibility in the radial direction inward to allow for clearing of a restriction or obstruction. Examples of restrictions include an unexpected section of heavy weight casing having a smaller inner diameter than expected or an immovable protrusion of the adjacent formation. The restriction can cause sticking of the cone since the pull force to drive the cone past the restriction is too high. This stuck cone creates a major time consuming and costly problem that can necessitate a sidetrack of the wellbore since the cone cannot be retrieved from the well and the cone is too hard to mill up.
Thus, there exists a need for an improved compliant cone capable of expanding a tubular while compensating for restrictions where expansion cannot occur.